Booms having three sections, fully extensible with axially connected rams



Dec. 31, 1968 R. .1. BRADY 3,419,157

BOOMS HAVING THREE SECTIONS, FULLY EXTENSIBLE WITH AXIALLY CQNNECTEDRAMS Sheet Filed April 25. 1967 INVENTOR J. BRADY ATTORNEYS R. J. BRADYDec. 31, 1968 BOOMS HAVING THR EE SECTIONS, FULLY EXTENSIBL WITH AXIALLYCONNECTED RAMS Filed April 25, 1967 Sheet INVENTOR BRADY RUPERTATTORNEYS United States Patent 3,419,157 BOGMS HAVING THREE SECTIDNS,FULLY EXTENSIBLE WITH AXIALLY CONNECTED RAMS Rupert J. Brady, 7201 PyleRoad, Bethesda, Md. 20034 Fiied Apr. 25, 1967, Ser. No. 633,510 3Ciaims. (Cl. 212-55) ABSTRACT OF THE DISCLOSURE An extensible boom, ofthe telescopic type for cranes, having at least three boom sectionsconnected for extension and retraction by a pair of multiple sectionhydraulic rams connected in substantially end-to-end relation interiorof the boom sections. Both of the rams are supported by a common memberconnected with the boom mid-section and extending longitudinally thereofwhereby the boom fly-section telescopes over said member and said pairof rams, in the retracted position.

A four section version of the boom includes a third double-acting ramconnected between two of the boom sections and interior thereof,disposed substantially parallel with the pair of rams, whereby the boomfly-section in the retracted position telescopes over all three rams,thereby providing a four section telescopic boom in which all sectionsare hydraulically extensible and in which there is only a slightvariation in the vertical cross-section dimension between all adjacentboom sections.

Background 0 the invention This invention is an improvement on theinvention disclosed in Patents 3,243,052 and 3,315,821 issued to John L.Grove on Mar. 29, 1966, and Apr. 25, 1967, respectively. These patentsdisclose three and four section extensible booms which are fullyhydraulically extensible by individual hydraulic rams positioned inside-by-side relation interior of the boom. In the three section fullyhydraulically extensible boom of Patent 3,243,052 the boom sections havea vertical height of a dimension to accommodate a pair of hydraulicran-rs, one above the other, interior of the boom. It is sometimesdesirable to have a fully extensible three section boom in which theheights of the boom sections are less than that required to house a pairof rams one above the other. it is thus the purpose of this invention toprovide such a boom structure and still provide the desirable featuresof all sections being selectively fully hydraulically extensible.

Up to this time four section extensible booms, in which all foursections are selectively fully extensible, have had a considerabledifference in the vertical crosssectional dimension between at least apair of the boom sections, usually between the base section and theinner midsection, because it has been necessary to connect a hydraulicram between the inner portion of the base section and outer portion ofthe other boom section, such that the other boom section does nottelescope over the ram. In the four section boom of the presentinvention all of the hydraulic rams are placed interior of all four boomsections so there is only a slight variance in the verticalcross-section dimension between all adjacent boom sections, just enoughso they can respectively telescope into each other. Since the verticaldimension or height of the vertical walls of the boom sections is one ofthe major design factors in the strength or lifting capacity of a boom,since the greater the height of the vertical walls the greater is theresistance to bending forces, this means that a four section boomaccording to the present inven- Patented Dec. 31, 1968 tion, with a basesection of the same wall height as the base section of thebefore-mentioned prior art boom, will have a substantially greaterlifting capacity because the vertical wall heights of the succeedingboom sections are all substantially greater than the wall heights in thecorresponding sections of the prior art boom.

These advances are brought about in the present invention by the use ofa pair of double-acting multisection telescopic rams connected insubstantially axial alignment between three of the boom sections. It isknown in the art to connect a pair of hydraulic rams in axial alignmentfor operating a two section boom but the art does not suggest how suchan arrangement can be utilized for providing a three section boom inwhich all of the sections are selectively hydraulically extensible, asin the present invention.

Summary of the invention The present invention provides an extensibletelescopic boom in which two of the sections are extensible from andretractable into the other section. This structure may be used in athree section telescopic boom configuration or in a four section, orgreater number of sections, telescopic boom configuration. In the threesection extensible boom configuration a mid-section is telescopicallydisposed in a base section and a fiy-section is telescopically disposedin the mid-section, with the differences in the cross-sections of therespective sections being just enough so that the sections caneffectively telescope within each other. A ram support member rigidlyconnected with the back of the mid-section extends longitudinallyinteriorly of the mid-section and terminates in a free end at a pointadjacent the outer end of the mid-section. A first multisection,double-acting telescopic hydraulic ram is pivotally connected betweenthe inner end of the base section and a point on the ram support memberintermediate the ends of said member. A second multisection,double-acting telescopic hydraulic ram is pivotally connected betweensubstantially the same point on the ram support member and the outer endof the fly-section, with this second ram connected in substantiallyaxial alignment with the firstmentioned ram. With this construction thefly-section telescopes over the ram support member and the pair ofaxially connected multisection rams in the retracted position. Frictionmeans are provided on the free end of the ram support member forcommonly supporting the weight of the front portion of the first ram andthe rear portion of the second ram on the inner surface of thefiy-section, preferably at a point forwardly of the connection of thetwo rams to the ram support member.

In the four section configuration of the boom the flysection, outermid-section and inner mid-section are COnnected in the same manner as inthe three section boom. The inner mid-section is disposed to telescopeinto a base section which has a cross-sectional size just sufficient toreceive the inner mid-section. The cross-sectional dimensions of thevarious sections thus diminish only slightly between adjacent boomsections, from the base section respectively out to the fly-section,thus obtaining the maximum vertical wall height in each boom section. Asecond ram support member is substantially rigidly connected to theinner end of the inner mid-section and extends longitudinally of theinterior thereof with the free terminal end provided with a meansdisposed in movable friction engagement with the interior surfaces ofthe fly and outer mid-sections during operation. A single, double-actinghydraulic ram is connected between the rear of the base section and apoint on the second ram support member for selectively extending andretracting the inner mid-section and the other boom sections carriedthereby, relative to the base section. With this construction, thefiy-section in the retractive position, as well as the outer mid-sectionand inner mid-section, in the retracted position, telescope over both ofsaid ram support members and the three hydraulic rams. With thisconstruction any bootm section can be selectively extended and retractedfrom its adjacent section, independently of the other sections.

Brief description of the drawings FIG. 1 is a schematic, vertical,longitudinal sectional view of the three section boom of the invention,the boom shown in the extended position;

FIG. 2 is a schematic view similar to FIG. 1, but showing the boom inretracted position;

FIG. 3 is an enlarged, foreshortened, longitudinal sectional view of theboom of FIG. 2, showing the boom in greater detail;

FIG. 4 is a schematic view showing the four section boom of theinvention in retracted position;

FIG. 5 is an enlarged, foreshortened, longitudinal sectional viewshowing the boom of FIG. 4 in greater detail;

FIG. 6 is an enlarged front elevational view of FIG. 5;

FIG. 7 is an enlarged, cross-sectional view taken substantially alongline 77 of FIG. 5 and particularly showing the pivot connection of thepair of rams to the common longitudinally extending support member; and

FIG. 8 is an enlarged rear elevational view of the boom of FIG. 5.

Description of the preferred embodiments Referring first to the threesection boom of FIGS. 1, 2 and 3, in greater detail, a rectangularcross-sectional base section 1 is disposed to be pivotally connected at2 to a boom support and to be pivoted to various elevation angles aboutpoint 2 by means of hydraulic ram means, not shown, pivotally connectedto the base section at 3. The present drawings disclose the boom in itssimplest detail with the reinforcing structure about the pivot points 2and 3 omitted for sake of clarity, but this structure is substantiallythe same as shown and described in the two mentioned Grove patents. Asubstantially rectangular cross-sectioned mid-section 4 istelescopically disposed in base section 1 and a substantiallyrectangular cross-sectioned fly-section 5 is telescopically disposed inmid-section 4. A boom nose assembly 6 is connected to the end of thefly-section in the normal manner as shown in dotted lines and a hoistcable 7 extends from a winch, not shown, on the crane body, through theupwardly opening cable guide channel 8, along the top of the boom andover the nose assembly for controlling a hook assembly, or the like, notshown, on the end thereof.

The cross-section modulus between adjacent succeeding boom sectionsvaries only by an amount which enables the various sections toeffectively telescope into each other. A ram support member 9 issubstantially rigidly connected at 10 by means of bracket members to therear portion of mid-section 4 and extends longitudinally of the interiorthereof, terminating in a free end 11 which is supported in movablefriction engagement by means of skids 12, or a roller assembly, notshown, with the interior bottom surface of fly-section 5 which isdisposed in surrounding relation to, and telescopes over, ram supportmember 9. Ram support member 9 is preferably of a length such that theskids 12 remain in contact with the inner surface of fly-section 5 inthe extended position of the fiy-section as shown in FIG. 1.

Ram support member 9 is substantially an integral part of mid-section 4and is preferably in the form of a rectangular cross-section housing,but may be in any form such as a rigid angle member, a pair ofinwardly-facing channel members or a rod, so long as it is sufficientlyrigid to partially support the weight of the pair of ram members, to bedescribed. A pair of double-acting, multiplesection hydraulic rams 13and 14, of the type well-known in the art, for instance each consistingof three telescopic sections 15, 16 and 17, are connected insubstantially axial alignment interior of all of the boom sections. Itis to be understood that the rams 13 and 14 may consist of more thanthree telescopic sections where required, depending upon the length ofthe boom sections to be extended. Hydraulic fluid is supplied to thedouble-acting multisection rams by means of hydraulic lines, not shown,in the usual manner, and spring-loaded takeup reel means, not shown, arealso provided in the usual manner for taking up and retracting thehydraulic lines as the boom sections are extended and retracted.

One end of hydraulic cylinder 15 of hydraulic ram 13 is pivotallyconnected at 18 to the inner end of base section 1 and the end of thetelescopic rod 17 is pivotally connected at 19 to a shaft assembly 20supported by ram support member 9, such as by extending transverselybetween the side walls of the ram support member. The end of cylindersection 15 of hydraulic ram 14 is pivotally connected by a pair ofclevis members 21 to shaft assembly 20 On opposite sides of pivotconnection 19 such that the cylinder end of ram 15 is supported by ramsupport member 9. It is to be understood that ram 14 may be connected tosupport member 9 by a separate shaft assembly 20, but in the preferredform, both rams are connected to ram support member 9 by the same shaftassembly 20. The end of rod section 17 of multisection hydraulic ram 14is pivotally connected at 22 to the outer end of fly-section 5.

It is to be noted that the multisection hydraulic rams 13 and 14 aredisposed in axial alignment within the housing of ram support member 9,in the retracted positions, FIGS. 2 and 3, such that the fly-sectiontelescopes over the ram support member 9 of the mid-section,substantially throughout its length and over the axially alignedhydraulic rams 13 and 14. This construction eliminates stacking ofhydraulic rams within a three section boom, and even though amultisection, double-acting hydraulic ram is larger in diameter than asingle piston-cylinder double-acting ram, the construction enables theprovision of a three section selectively extensible boom, in which theoverall vertical wall height of the boom sections is reduced from thatrequired when cylinders are stacked and the construction still providesa boom in which the cross-section modulus of succeeding boom sectionsvaries only slightly.

Part of the weight of both rams is supported by skid 12 which ispositioned forwardly of shaft assembly 20 by a sufficient amount so thatit always remains in sliding contact with the interior bottom surface offiy-section 5. By this construction, ram 14 in effect is connected tothe inner or rear end of mid-section 4, and the rod end of ram 13, isalso effectively connected to the rear end of mid-section 4, but yettheir connection point to the midsection is substantially medial of themid-section.

The tour section version of the telescopic boom of the invention isdisclosed in FIGS, 4-8, wherein similar reference numerals refer to likecomponents and primed reference numerals refer to correspondingcomponents disclosed in the three section version of the boom. It is tobe understood that the cross-section views of the four section boom alsodisclose the cross-sectional construction of the three section boom. Thefour section boom comprises a base section 23, an inner mid-section 1',an outer mid-section 4 and a fly-section 5', all of generallyrectangular cross-section and respectively telescoped into each other,such that there is only a slight difference in the cross-section modulusof succeeding boom sections. Bearing pads 24 are connected adjacent thefronts of boom sections 23, 1' and 4 and on the upper rear surfaces ofsections 4 and 5 in the usual manner to aid in smooth s1idin operationof the boom sections. A roller assembly 26, connected to the rear ofboom section 1' and disposed in rolling engagement with the inner topsurface of boom section 23, may be used in lieu of bearing padsthroughout the structure. Bearing shim plates 25 are appropriatelyconnected as shown between the various surfaces of adjacent boomsections, in the normal manner to eliminate slack movement betweenadjacent sections. The bearing shim plates 25 and bearing pads 24 may beconstructed of brass or other suitable bearing material. Bearing pads 24and bearing shim plates 25 are connected in the same manner between thevarious boom sections of the three section boom as shown in FIG. 3. Itis to be understood that the boom sections -1, 4' and 5 are constructedand connected for operation with each other in substantially the samemanner as corresponding boom sections 1, 4 and 5 in FIGS. 1-3, with theexception that the heights of the vertical walls of the boom sectionsare greater in order to accommodate a further hydraulic ram beneath thepair of multisection hydraulic rams 13' and 14. The multisectionhydraulic rams 13' and 14 are respectively pivotally connected betweeninner mid-section 1 and shaft assembly 20 of ram support member 9', andthe shaft assembly 20 and fiy-section 5. This pair of multisection ramsis housed in ram support member 9' which in turn commonly supports partof the weight of the rams on the inner surface of the fiy-section by theenlarged skids, or roller assemblies, not shown, 12.

A second ram support member 27, of substantially the same configurationas member 9, is substantially rigidly connected by bracket members 28 tothe rear of inner mid-section 1, at a position beneath ram supportmember 9'. Second ram support member 27 extends longitudinally of theinterior of the inner mid-section 1, and in retracted position, extendsinteriorly of sections 4' and 5', and its free end is disposed inmovable friction engagement with the interior surface of fly-section 5'and outer mid-section 4' by means of skids 29 or by means of a rollerassembly, not shown. A double-acting hydraulic ram 30 is disposed in thesecond ram support member 27, in retracted position, with the end of itscylinder 31 pivotally connected at 32 to the inner end of base section23, and the end of its rod 33 pivotally connected at 34 to second ramsupport member 27 through the shaft assembly 35. The weight of ram 30and second ram support member 29 is thus partially supported by theskids 29 on the other boom sections and with this construction hydraulicram 30 in effect is connected to the front portion of inner midsection1' with no transversely extending connecting pin to block the passage ofsections 4 and 5 from telescoping into section 1. Hydraulic ram 30 isdisposed substantially parallel with the pair of axially alignedmultisection hydraulic rams 13' and 14, and the ram support members 9and 27 are disposed one above the other and substantially parallel Witheach other. With this construction for a given vertical wall height ofbase section 23,

a substantially greater vertical wall height is provided in boomsections 1, 4 and 5', because the construction allows for all three ramsto be positioned interiorly of the boom sections so that the fly-sectiontelescopes over all three rams and the two ram support members in theretractible position. In the prior art the vertical wall heights ofsections comparable to sections 5, 4 and 1' were considerably less thanthe vertical wall height of the base section because one of thehydraulic rams was positioned exteriorly of the inner mid-section. Thepresent invention thus makes the outer three sections capable of liftingheavier loads than comparable booms in the prior art as it enables themto provide greater resistance to bending stresses due to the increase inthe vertical wall heights of the sections relative to the height of thebase section wall.

I claim:

1. A boom having at least four telescopic extensible sectionscomprising, a first section, a second section telescopically disposed insaid first section, a third section telescopically disposed in saidsecond section, means connected to one end of said second section andextending longitudinally of the interior thereof, said means having afree end in proximity to the outer end of said second section, supportmeans connected to said free end and disposed in movable frictionengagement with the inner surface of said third section, a firstmultisection double-acting hydraulic ram independently pivotallyconnected to said first section and said means to extend and retractsaid second section, a second multisection double-acting hydraulic ramindependently pivotally connected to said means and said third sectionto extend and retract said third section, said second multisection ramconnected in spaced relation with and in substantial axial alignmentwith said first multisection ram, and said first and second multisectionrams connected to said means in the proximity of the medial portion ofsaid second section, whereby said third section telescopes over saidfirst and second multisection rams and said means in the retractedposition of said boom, and said first and second multisection rams areindividually supported by said means and said support means, a fourthsection telescopically receiving said first section, a second meansconnected at one end to the corresponding end of said first section andextending longitudinally of the interior thereof substantially parallelwith said first mentioned longitudinally extending means, a thirdhydraulic ram connected to said fourth section and said second means toextend and retract said first section relative to said fourth section,and said third section disposed to telescope over said second and firstmentioned longitudinally extending means and said first, second andthird rams in the retracted position.

2. A boom as set forth in claim 1 in which said second longitudinallyextending means is disposed in the same vertical plane as said firstmentioned longitudinally extending means and includes a free end, secondsupport means connected to said free end an ddisposed in movablefriction engagement with the interior of said third and second sectionsas the sections are extended and retracted.

3. A boom as set forth in claim 1 in which said third hydraulic ramcomprises a single cylinder-piston doubleacting hydraulic ram positionedbeneath said first and second multisection rams.

References Cited UNITED STATES PATENTS 3,243,052 3/1966 Grove 212-4443,259,251 7/1966 Stauffer 212- 3,353,686 11/1967 Cowan 21255 EDWARD A.SROKA, Primary Examiner. H. C. HORNSBY, Assistant Examiner.

